U.S. patent application number 15/081540 was filed with the patent office on 2017-09-28 for systems and methods for thermal management in wireless power transfer.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Simon Islinger, Edward van Boheemen, Felix Weidner, Michael Werner.
Application Number | 20170274778 15/081540 |
Document ID | / |
Family ID | 58192382 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170274778 |
Kind Code |
A1 |
van Boheemen; Edward ; et
al. |
September 28, 2017 |
SYSTEMS AND METHODS FOR THERMAL MANAGEMENT IN WIRELESS POWER
TRANSFER
Abstract
The invention described herein relates to wireless power
transfer systems and methods that efficiently and safely transfer
power to electronic devices. In an aspect of the disclosure, an
apparatus for wirelessly receiving power is provided. The apparatus
may comprise a receiver circuit comprising a receiver coil
configured to receive wireless power from a wireless power
transmitter via a magnetic field sufficient to charge or power a
load of the apparatus. The receiver circuit further comprises a
ferrite material having a first side coupled to the receiver coil.
The apparatus further comprises a first heat exchanger coupled to a
second side of the ferrite material.
Inventors: |
van Boheemen; Edward;
(Mumich, DE) ; Islinger; Simon; (Muenchen, DE)
; Weidner; Felix; (Munich, DE) ; Werner;
Michael; (Markt Schwaben, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
58192382 |
Appl. No.: |
15/081540 |
Filed: |
March 25, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 10/70 20130101;
H02J 7/025 20130101; H01F 27/36 20130101; B60L 53/126 20190201;
B60L 53/122 20190201; H01F 27/16 20130101; H02J 50/70 20160201;
H02J 7/027 20130101; H01F 38/14 20130101; Y02T 10/7072 20130101;
B60L 53/38 20190201; B60L 53/302 20190201; H02J 50/10 20160201;
B60L 53/36 20190201; H01F 27/22 20130101; Y02T 90/14 20130101; Y02T
90/12 20130101; B60L 11/182 20130101 |
International
Class: |
B60L 11/18 20060101
B60L011/18; H02J 50/10 20060101 H02J050/10; H02J 7/02 20060101
H02J007/02 |
Claims
1. An apparatus for wirelessly receiving power, the apparatus
comprising: a receiver circuit comprising: a receiver coil
configured to receive wireless power from a wireless power
transmitter via a magnetic field sufficient to charge or power a
load of the apparatus, and a ferrite material having a first side
coupled to the receiver coil; and a first heat exchanger coupled to
a second side of the ferrite material.
2. The apparatus of claim 1, wherein the first heat exchanger is
disposed within an area defined by the second side of the ferrite
material.
3. The apparatus of claim 1, wherein the first heat exchanger is
configured to cool the receiver circuit.
4. The apparatus of claim 1, wherein the first heat exchanger
comprises a metallic material.
5. The apparatus of claim 1, wherein the first heat exchanger
comprises a cavity for guiding a flow of a cooling liquid.
6. The apparatus of claim 1, wherein the first heat exchanger
comprises a plurality of metallic extensions disposed on the
ferrite material substantially parallel to magnetic field lines of
the magnetic field.
7. The apparatus of claim 1, further comprising a second heat
exchanger thermally coupled to the first heat exchanger disposed
outside an area of the receiver circuit.
8. The apparatus of claim 1, further comprising a second heat
exchanger thermally coupled to and surrounding the first heat
exchanger.
9. The apparatus of claim 7, wherein the second heat exchanger
comprises a metallic material.
10. The apparatus of claim 1, further comprising an electronic
circuit coupled to the first heat exchanger.
11. A method for wirelessly receiving power, the method comprising:
receiving, via a receiver circuit, wireless power via a magnetic
field generated by a wireless power transmitter, the wireless power
at a level sufficient to charge or power a wireless power receiver,
the receiver circuit comprising a receiver coil and a ferrite
material having a first side coupled to the receiver coil; and
cooling the receiver circuit using a first heat exchanger coupled
to a second side of the ferrite material.
12. The method of claim 11, wherein the first heat exchanger is
disposed within an area defined by the second side of the ferrite
material.
13. The method of claim 11, wherein the first heat exchanger
comprises a metallic material.
14. The method of claim 11, wherein the first heat exchanger
comprises a cavity for guiding a flow of a cooling liquid.
15. The method of claim 11, wherein the first heat exchanger
comprises a plurality of metallic extensions disposed on the
ferrite material substantially parallel to magnetic field lines of
the magnetic field.
16. The method of claim 11, further comprising cooling the receiver
circuit using a second heat exchanger thermally coupled to the
first heat exchanger disposed outside an area of the receiver
circuit.
17. The method of claim 11, further comprising cooling the receiver
circuit using a second heat exchanger thermally coupled to and
surrounding the first heat exchanger.
18. The method of claim 16, wherein the second heat exchanger
comprises a metallic material.
19. The method of claim 17, wherein the second heat exchanger
comprises a metallic material.
20. The method of claim 11, further comprising placing an
electronic circuit coupled to the first heat exchanger.
21. An apparatus for wirelessly receiving power, the apparatus
comprising: means for receiving wireless power from a wireless
power transmitter via a magnetic field sufficient to charge or
power a load of the apparatus, a ferrite material having a first
side coupled to the means for receiving; and first means for
cooling the receiving means coupled to a second side of the ferrite
material.
22. The apparatus of claim 21, wherein the first means for cooling
is disposed within an area defined by the second side of the
ferrite material.
23. The apparatus of claim 21, wherein the first means for cooling
comprises a metallic material.
24. The apparatus of claim 21, wherein the first means for cooling
comprises a cavity for guiding a flow of a cooling liquid.
25. The apparatus of claim 21, wherein the means for cooling
comprises a plurality of metallic extensions disposed on the
ferrite material substantially parallel to magnetic field lines of
the magnetic field.
26. The apparatus of claim 21, further comprising a second means
for cooling thermally coupled to the first means for cooling
disposed outside an area of the receiving means.
27. The apparatus of claim 21, further comprising a second means
for cooling thermally coupled to and surrounding the first means
for cooling.
28. The apparatus of claim 26, wherein the second means for cooling
comprises a metallic material.
29. The apparatus of claim 27, wherein the second means for cooling
comprises a metallic material.
30. The apparatus of claim 21, further comprising means for
controlling wireless power transfer coupled to the first means for
cooling.
Description
TECHNICAL FIELD
[0001] This application is generally related to wireless power
transfer, and in particular, thermal management of wireless power
devices such as electric vehicles during wireless power
transfer.
BACKGROUND
[0002] Chargeable systems, such as vehicles, have been introduced
that include locomotion power derived from electricity received
from an energy storage device such as a battery. For example,
hybrid electric vehicles include on-board chargers that use power
from vehicle braking and traditional motors to charge the vehicles.
Vehicles that are solely electric generally receive the electricity
for charging the batteries from other sources. Battery electric
vehicles are often proposed to be charged through some type of
wired alternating current (AC) such as household or commercial AC
supply sources. The wired charging connections require cables or
other similar connectors that are physically connected to a power
supply. Cables and similar connectors may sometimes be inconvenient
or cumbersome and have other drawbacks. It is desirable to provide
wireless power transfer systems that are capable of transferring
power in free space (e.g., via a wireless field) to be used to
charge the electric vehicle to overcome some of the deficiencies of
wired charging solutions.
SUMMARY
[0003] The systems, methods, and devices of the invention each have
several aspects, no single one of which is solely responsible for
its desirable attributes. The implementations disclosed herein each
have several innovative aspects, no single one of which is solely
responsible for the desirable attributes of the invention. Without
limiting the scope of this invention as expressed by the claims
which follow, some features will now be discussed briefly. After
considering this discussion, and particularly after reading the
section entitled "Detailed Description," one will understand how
the features of the various implementations of this invention
provide advantages that include improved wireless charging between
wireless power transmitting units and wireless power receiving
units.
[0004] In an aspect of the disclosure, an apparatus for wirelessly
receiving power is provided. The apparatus may comprise a receiver
circuit comprising a receiver coil configured to receive wireless
power from a wireless power transmitter via a magnetic field
sufficient to charge or power a load of the apparatus. The receiver
circuit further comprising a ferrite material having a first side
coupled to the receiver coil. The apparatus may further comprise a
first heat exchanger coupled to a second side of the ferrite
material.
[0005] In another aspect of the disclosure, a method for wirelessly
receiving power is provided. The method includes receiving, via a
receiver circuit, wireless power via a magnetic field generated by
a wireless power transmitter. The wireless power received at a
level sufficient to charge or power a wireless power receiver. The
receiver circuit comprising a receiver coil and a ferrite material
having a first side coupled to the receiver coil.
[0006] In another aspect of the disclosure, an apparatus for
wirelessly receiving power is provided. The apparatus comprises
means for receiving wireless power from a wireless power
transmitter via a magnetic field sufficient to charge or power a
load of the apparatus. The apparatus further comprises a ferrite
material having a first side coupled to the means for receiving.
The apparatus further comprises means for cooling the receiving
means coupled to a second side of the ferrite material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The above-mentioned aspects, as well as other features,
aspects, and advantages of the present technology will now be
described in connection with various embodiments, with reference to
the accompanying drawings. The illustrated embodiments, however,
are merely examples and are not intended to be limiting. Throughout
the drawings, similar symbols typically identify similar
components, unless context dictates otherwise. Note that the
relative dimensions of the following figures may not be drawn to
scale.
[0008] FIG. 1 is a functional block diagram of a wireless power
transfer system, in accordance with one example of an
implementation.
[0009] FIG. 2 is a functional block diagram of a wireless power
transfer system, in accordance with another example
implementation.
[0010] FIG. 3 is a functional block diagram of a wireless power
transfer system, in accordance with another example
implementation.
[0011] FIG. 4A is a diagram of a wireless power transfer system
comprising a metallic heat sink, in accordance with another example
implementation.
[0012] FIG. 4B is a diagram of a wireless power transfer system
comprising a metallic heat sink, in accordance with another example
implementation.
[0013] FIG. 5A is a diagram of a wireless power transfer system
comprising a metallic heat sink, in accordance with another example
implementation.
[0014] FIG. 5B is a diagram of a wireless power transfer system
comprising a first metallic heat sink and a second metallic heat
sink, in accordance with another example implementation.
[0015] FIG. 6A is a diagram of a wireless power transfer system
comprising a non-metallic heat sink, in accordance with another
example implementation.
[0016] FIG. 6B is a diagram of a wireless power transfer system
comprising a non-metallic heat sink and an electronic circuit, in
accordance with another example implementation.
[0017] FIG. 7A is a diagram of a wireless power transfer system
comprising a non-metallic heat sink and a non-metallic heat
exchanger according to another exemplary embodiment.
[0018] FIG. 7B is a diagram of a wireless power transfer system
comprising a non-metallic heat sink, a non-metallic heat exchanger,
and an electronic circuit according to another exemplary
embodiment.
[0019] FIG. 8 is a diagram of a wireless power transfer system
comprising a liquid heat sink according to another exemplary
embodiment.
[0020] FIG. 9 is a flowchart depicting a method for managing
thermal power losses according to the disclosure.
DETAILED DESCRIPTION
[0021] In the following detailed description, reference is made to
the accompanying drawings, which form a part of the present
disclosure. The illustrative embodiments described in the detailed
description, drawings, and claims are not meant to be limiting.
Other embodiments may be utilized, and other changes may be made,
without departing from the spirit or scope of the subject matter
presented here. It will be readily understood that the aspects of
the present disclosure, as generally described herein, and
illustrated in the Figures, can be arranged, substituted, combined,
and designed in a wide variety of different configurations, all of
which are explicitly contemplated and form part of this
disclosure.
[0022] Wireless power transfer may refer to transferring any form
of energy associated with electric fields, magnetic fields,
electromagnetic fields, or otherwise from a transmitter to a
receiver without the use of physical electrical conductors (e.g.,
power may be transferred through free space). The power output into
a wireless field (e.g., a magnetic field or an electromagnetic
field) may be received, captured by, or coupled by a "receive
antenna" to achieve power transfer.
[0023] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. It will be understood by those within the art that
if a specific number of a claim element is intended, such intent
will be explicitly recited in the claim, and in the absence of such
recitation, no such intent is present. For example, as used herein,
the singular forms "a," "an," and "the" are intended to include the
plural forms as well, unless the context clearly indicates
otherwise. As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items. It will
be further understood that the terms "comprises," "comprising,"
"includes," and "including," when used in this specification,
specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
Expressions such as "at least one of," when preceding a list of
elements, modify the entire list of elements and do not modify the
individual elements of the list.
[0024] Electrical and electronic processes often generate waste
heat. Waste heat is energy that is necessarily produced by
processes requiring energy, such as electrical and electronic
processes, including wired and wireless power transfer and charging
operations. As generally referred to herein, waste heat may also
include thermal power dissipation of one or more of the devices
involved in wireless power transfer. "Waste heat" may alternatively
be referred to herein as "heat power dissipation" or "thermal power
dissipation." The terms may generally be used interchangeably.
[0025] Although relatively small in magnitude, waste heat in
electronics may adversely affect the performance of an electronic
device, e.g., a mobile device such as those described below.
Increased temperatures may result in decreased efficiency of
charging operations and shortened operating life of a power storage
device, for example, a battery being charged, or the electronic
device, for example, a mobile wireless device. Thus, efficient
dissipation or disposal of waste heat in electronics may increase
efficiency and operating life of the components.
[0026] In a wireless power transfer system similar to those
described herein, a wireless power transmitter transfers wireless
power to a wireless power receiver. In operation, the transmitter
and the receiver may be in close proximity or in contact with one
another in order to optimize the transfer of wireless power. In
general, one or both of the transmitter and receiver may increase
in temperature during the charging operations. As inductive power
is transferred some of the energy is lost as waste heat.
Accordingly, one or both of the transmitter and the receiver may
increase in temperature during power transfer.
[0027] In some embodiments, wireless power receiver induction coils
in wireless electric vehicle charging (WEVC) applications can
generate significant losses in power transfer. In some aspects, due
to smaller and smaller vehicle pads including the receiver
induction coils, it may be difficult to get losses out of the
vehicle pad/induction coil. Adding an aluminium or other metallic
heatsinks for passive cooling may not be preferable since the
magnetic fields would generate additional losses in the cooling
components if they are in close proximity to the induction coils of
the wireless power transmitter/receiver. In some aspects, forced
air cooling applications may also be not preferred or available
under the car, so it may not be an option. Additionally, increased
temperature of the transmitter and/or receiver may lead to a
reduction in charge capability. This may further result in
increased charging times.
[0028] In order to increase wireless power transfer from the
transmitter to the receiver, a number of thermal management
solutions may be implemented. In some aspects, it may be beneficial
to actively cool the vehicle pad and/or transmitter without
additional loss generation. This would enable further size
reduction of vehicle pads. For example, embodiments described
herein relate to utilizing metallic and non-metallic active cooling
methods and devices to cool wireless power receivers and/or
transmitters.
[0029] FIG. 1 is a diagram of a wireless power transfer system 100
for charging an electric vehicle 112, in accordance with some
implementations. The wireless power transfer system 100 enables
charging of an electric vehicle 112 while the electric vehicle 112
is parked near a base wireless charging system 102a. Spaces for two
electric vehicles are illustrated in a parking area to be parked
over corresponding base wireless charging system 102a and 102b. In
some implementations, a local distribution center 190 may be
connected to a power backbone 192 and configured to provide an
alternating current (AC) or a direct current (DC) supply through a
power link 110 to the base wireless charging system 102a. The base
wireless charging system 102a also includes a base system induction
coil 104a for wirelessly transferring or receiving power. An
electric vehicle 112 may include a battery unit 118, an electric
vehicle induction coil 116, and an electric vehicle wireless
charging system 114. The electric vehicle induction coil 116 may
interact with the base system induction coil 104a for example, via
a region of the magnetic field generated by the base system
induction coil 104a.
[0030] In some implementations, the electric vehicle induction coil
116 may receive power when the electric vehicle induction coil 116
is located in an energy field produced by the base system induction
coil 104a. The field corresponds to a region where energy output by
the base system induction coil 104a may be captured by an electric
vehicle induction coil 116. For example, the energy output by the
base system induction coil 104a may be at a level sufficient to
charge or power the electric vehicle 112. In some cases, the field
may correspond to the "near field" of the base system induction
coil 104a. The near-field may correspond to a region in which there
are strong reactive fields resulting from the currents and charges
in the base system induction coil 104a that do not radiate power
away from the base system induction coil 104a. In some cases the
near-field may correspond to a region that is within about 1/2.pi.
of wavelength of the base system induction coil 104a (and vice
versa for the electric vehicle induction coil 116) as will be
further described below.
[0031] Local distribution 130 may be configured to communicate with
external sources 132 (e.g., a power grid) via a communication
backhaul 134, and with the base wireless charging system 102a via a
communication link 108.
[0032] In some implementations the electric vehicle induction coil
116 may be aligned with the base system induction coil 104a and,
therefore, disposed within a near-field region simply by the driver
positioning the electric vehicle 112 correctly relative to the base
system induction coil 104a. In other implementations, the driver
may be given visual feedback, auditory feedback, or combinations
thereof to determine when the electric vehicle 112 is properly
placed for wireless power transfer. In yet other implementations,
the electric vehicle 112 may be positioned by an autopilot system,
which may move the electric vehicle 112 back and forth (e.g., in
zig-zag movements) until an alignment error has reached a tolerable
value. This may be performed automatically and autonomously by the
electric vehicle 112 without or with only minimal driver
intervention provided that the electric vehicle 112 is equipped
with a servo steering wheel, ultrasonic sensors, and intelligence
to adjust the vehicle. In still other implementations, the electric
vehicle induction coil 116, the base system induction coil 104a, or
a combination thereof may have functionality for displacing and
moving the induction coils 116 and 104a relative to each other to
more accurately orient them and develop more efficient coupling
therebetween.
[0033] The base wireless charging system 102a may be located in a
variety of locations. As non-limiting examples, some suitable
locations include a parking area at a home of the electric vehicle
112 owner, parking areas reserved for electric vehicle wireless
charging modeled after conventional petroleum-based filling
stations, and parking lots at other locations such as shopping
centers and places of employment.
[0034] Charging electric vehicles wirelessly may provide numerous
benefits. For example, charging may be performed automatically,
virtually without driver intervention and manipulations thereby
improving convenience to a user. There may also be no exposed
electrical contacts and no mechanical wear out, thereby improving
reliability of the wireless power transfer system 100.
Manipulations with cables and connectors may not be needed, and
there may be no cables, plugs, or sockets that may be exposed to
moisture and water in an outdoor environment, thereby improving
safety. There may also be no sockets, cables, and plugs visible or
accessible, thereby reducing potential vandalism of power charging
devices. Further, since an electric vehicle 112 may be used as
distributed storage devices to stabilize a power grid, a
docking-to-grid solution may be used to increase availability of
vehicles for Vehicle-to-Grid (V2G) operation.
[0035] A wireless power transfer system 100 as described with
reference to FIG. 1 may also provide aesthetical and
non-impedimental advantages. For example, there may be no charge
columns and cables that may be impedimental for vehicles and/or
pedestrians.
[0036] As a further explanation of the vehicle-to-grid capability,
the wireless power transmit and receive capabilities may be
configured to be reciprocal such that the base wireless charging
system 102a transfers power to the electric vehicle 112 and the
electric vehicle 112 transfers power to the base wireless charging
system 102a e.g., in times of energy shortfall. This capability may
be useful to stabilize the power distribution grid by allowing
electric vehicles to contribute power to the overall distribution
system in times of energy shortfall caused by over demand or
shortfall in renewable energy production (e.g., wind or solar).
[0037] FIG. 2 is a schematic diagram of core components of the
wireless power transfer system 100 of FIG. 1. As shown in FIG. 2,
the wireless power transfer system 200 may include a base system
transmit circuit 206 including a base system induction coil 204
having an inductance L.sub.1. The wireless power transfer system
200 further includes an electric vehicle receive circuit 222
including an electric vehicle induction coil 216 having an
inductance L.sub.2. Implementations described herein may use
capacitively loaded wire loops (i.e., multi-turn coils) forming a
resonant structure that is capable of efficiently coupling energy
from a primary structure (transmitter) to a secondary structure
(receiver) via a magnetic or electromagnetic near field if both
primary and secondary are tuned to a common resonant frequency. The
coils may be used for the electric vehicle induction coil 216 and
the base system induction coil 204. Using resonant structures for
coupling energy may be referred to "magnetic coupled resonance,"
"electromagnetic coupled resonance," and/or "resonant induction."
The operation of the wireless power transfer system 200 will be
described based on power transfer from a base wireless charging
system 202 to an electric vehicle 112, but is not limited thereto.
For example, as discussed above, the electric vehicle 112 may
transfer power to the base wireless charging system 102a.
[0038] With reference to FIG. 2, a power supply 208 (e.g., AC or
DC) supplies power P.sub.SDC to the base wireless charging system
202 to transfer energy to an electric vehicle 112. The base
wireless charging system 202 includes a base charging system power
converter 336. The base charging system power converter 236 may
include circuitry such as an AC/DC converter configured to convert
power from standard mains AC to DC power at a suitable voltage
level, and a DC/low frequency (LF) converter configured to convert
DC power to power at an operating frequency suitable for wireless
high power transfer. The base charging system power converter 236
supplies power P.sub.1 to the base system transmit circuit 206
including the capacitor C.sub.1 in series with the base system
induction coil 204 to emit a magnetic field at a desired frequency.
The capacitor C.sub.1 may be coupled with the base system induction
coil 204 either in parallel or in series, or may be formed of
several reactive elements in any combination of parallel or series
topology. The capacitor C.sub.1 may be provided to form a resonant
circuit with the base system induction coil 204 that resonates at a
desired frequency. The base system induction coil 204 receives the
power P.sub.1 and wirelessly transmits power at a level sufficient
to charge or power the electric vehicle 112. For example, the power
level provided wirelessly by the base system induction coil 204 may
be on the order of kilowatts (kW) (e.g., anywhere from 1 kW to 110
kW or higher or lower) and, in some implementations, may be
transferred at frequencies including but not limited to 85 kHz.
[0039] The base system transmit circuit 206 including the base
system induction coil 204 and electric vehicle receive circuit 222
including the electric vehicle induction coil 216 may be tuned to
substantially the same frequencies and may be positioned within the
near-field of a magnetic field transmitted by one of the base
system induction coil 204 and the electric vehicle induction coil
116. In this case, the base system induction coil 204 and electric
vehicle induction coil 116 may become coupled to one another such
that power may be transferred to the electric vehicle receive
circuit 222 including capacitor C.sub.2 and electric vehicle
induction coil 116. The capacitor C.sub.2 may be provided to form a
resonant circuit with the electric vehicle induction coil 216 that
resonates at a desired frequency. The capacitor C.sub.2 may be
coupled with the electric vehicle induction coil 204 either in
parallel or in series, or may be formed of several reactive
elements in any combination of parallel or series topology. Element
k(d) represents the mutual coupling coefficient resulting at coil
separation. Equivalent resistances R.sub.eq,1 and R.sub.eq,2
represent the losses that may be inherent to the induction coils
204 and 216 and the anti-reactance capacitors C.sub.1 and C.sub.2.
The electric vehicle receive circuit 222 including the electric
vehicle induction coil 216 and capacitor C.sub.2 receives power
P.sub.2 and provides the power P.sub.2 to an electric vehicle power
converter 238 of an electric vehicle charging system 214.
[0040] The electric vehicle power converter 238 may include, among
other things, a LF/DC converter configured to convert power at an
operating frequency back to DC power at a voltage level matched to
the voltage level of an electric vehicle battery unit 218. The
electric vehicle power converter 238 may provide the converted
power P.sub.LDC to charge the electric vehicle battery unit 218.
The power supply 208, base charging system power converter 236, and
base system induction coil 204 may be stationary and located at a
variety of locations as discussed above. The battery unit 218,
electric vehicle power converter 238, and electric vehicle
induction coil 216 may be included in an electric vehicle charging
system 214 that is part of electric vehicle 112 or part of the
battery pack (not shown). The electric vehicle charging system 214
may also be configured to provide power wirelessly through the
electric vehicle induction coil 216 to the base wireless charging
system 202 to feed power back to the grid. Each of the electric
vehicle induction coil 216 and the base system induction coil 204
may act as transmit or receive induction coils based on the mode of
operation.
[0041] While not shown, the wireless power transfer system 200 may
include a load disconnect unit (LDU) to safely disconnect the
electric vehicle battery unit 218 or the power supply 208 from the
wireless power transfer system 200. For example, in case of an
emergency or system failure, the LDU may be triggered to disconnect
the load from the wireless power transfer system 200. The LDU may
be provided in addition to a battery management system for managing
charging to a battery, or it may be part of the battery management
system.
[0042] Further, the electric vehicle charging system 214 may
include switching circuitry (not shown) for selectively connecting
and disconnecting the electric vehicle induction coil 216 to the
electric vehicle power converter 238. Disconnecting the electric
vehicle induction coil 216 may suspend charging and also may adjust
the "load" as "seen" by the base wireless charging system 102a
(acting as a transmitter), which may be used to "cloak" the
electric vehicle charging system 114 (acting as the receiver) from
the base wireless charging system 102a. The load changes may be
detected if the transmitter includes the load sensing circuit.
Accordingly, the transmitter, such as a base wireless charging
system 202, may have a mechanism for determining when receivers,
such as an electric vehicle charging system 114, are present in the
near-field of the base system induction coil 204.
[0043] As described above, in operation, assuming energy transfer
towards the vehicle or battery, input power is provided from the
power supply 208 such that the base system induction coil 204
generates a field for providing the energy transfer. The electric
vehicle induction coil 216 couples to the radiated field and
generates output power for storage or consumption by the electric
vehicle 112. As described above, in some implementations, the base
system induction coil 204 and electric vehicle induction coil 116
are configured according to a mutual resonant relationship such
that when the resonant frequency of the electric vehicle induction
coil 116 and the resonant frequency of the base system induction
coil 204 are very close or substantially the same. Transmission
losses between the base wireless charging system 202 and electric
vehicle charging system 214 are minimal when the electric vehicle
induction coil 216 is located in the near-field of the base system
induction coil 204.
[0044] As stated, an efficient energy transfer occurs by coupling a
large portion of the energy in the near field of a transmitting
induction coil to a receiving induction coil rather than
propagating most of the energy in a magnetic wave to the far-field.
When in the near field, a coupling mode may be established between
the transmit induction coil and the receive induction coil. The
area around the induction coils where this near field coupling may
occur is referred to herein as a near field coupling mode
region.
[0045] While not shown, the base charging system power converter
236 and the electric vehicle power converter 238 may both include
an oscillator, a driver circuit such as a power amplifier, a
filter, and a matching circuit for efficient coupling with the
wireless power induction coil. The oscillator may be configured to
generate a desired frequency, which may be adjusted in response to
an adjustment signal. The oscillator signal may be amplified by a
power amplifier with an amplification amount responsive to control
signals. The filter and matching circuit may be included to filter
out harmonics or other unwanted frequencies and match the impedance
of the power conversion module to the wireless power induction
coil. The power converters 236 and 238 may also include a rectifier
and switching circuitry to generate a suitable power output to
charge the battery.
[0046] The electric vehicle induction coil 216 and base system
induction coil 204 as described throughout the disclosed
implementations may be referred to or configured as "loop"
antennas, and more specifically, multi-turn loop antennas. The
induction coils 204 and 216 may also be referred to herein or be
configured as "magnetic" antennas. The term "coils" is intended to
refer to a component that may wirelessly output or receive energy
four coupling to another "coil." The coil may also be referred to
as an "antenna" of a type that is configured to wirelessly output
or receive power. As used herein, coils 204 and 216 are examples of
"power transfer components" of a type that are configured to
wirelessly output, wirelessly receive, and/or wirelessly relay
power. Loop (e.g., multi-turn loop) antennas may be configured to
include an air core or a physical core such as a ferrite core. An
air core loop antenna may allow the placement of other components
within the core area. Physical core antennas including
ferromagnetic or ferromagnetic materials may allow development of a
stronger magnetic field and improved coupling.
[0047] As discussed above, efficient transfer of energy between a
transmitter and receiver occurs during matched or nearly matched
resonance between a transmitter and a receiver. However, even when
resonance between a transmitter and receiver are not matched,
energy may be transferred at a lower efficiency. Transfer of energy
occurs by coupling energy from the near field of the transmitting
induction coil to the receiving induction coil residing within a
region (e.g., within a predetermined frequency range of the
resonant frequency, or within a predetermined distance of the
near-field region) where this near field is established rather than
propagating the energy from the transmitting induction coil into
free space.
[0048] A resonant frequency may be based on the inductance and
capacitance of a transmit circuit including an induction coil
(e.g., the base system induction coil 204) as described above. As
shown in FIG. 2, inductance may generally be the inductance of the
induction coil, whereas, capacitance may be added to the induction
coil to create a resonant structure at a desired resonant
frequency. As a non-limiting example, as shown in FIG. 2, a
capacitor may be added in series with the induction coil to create
a resonant circuit (e.g., the base system transmit circuit 206)
that generates a magnetic field. Accordingly, for larger diameter
induction coils, the value of capacitance needed to induce
resonance may decrease as the diameter or inductance of the coil
increases. Inductance may also depend on a number of turns of an
induction coil. Furthermore, as the diameter of the induction coil
increases, the efficient energy transfer area of the near field may
increase. Other resonant circuits are possible. As another non
limiting example, a capacitor may be placed in parallel between the
two terminals of the induction coil (e.g., a parallel resonant
circuit). Furthermore an induction coil may be designed to have a
high quality (Q) factor to improve the resonance of the induction
coil. For example, the Q factor may be 300 or greater.
[0049] As described above, according to some implementations,
coupling power between two induction coils that are in the near
field of one another is disclosed. As described above, the near
field may correspond to a region around the induction coil in which
magnetic fields exist but may not propagate or radiate away from
the induction coil. Near-field coupling-mode regions may correspond
to a volume that is near the physical volume of the induction coil,
typically within a small fraction of the wavelength. According to
some implementations, magnetic induction coils, such as single and
multi-turn loop antennas, are used for both transmitting and
receiving since magnetic near field amplitudes in practical
implementations tend to be higher for magnetic type coils in
comparison to the electric near fields of an electric type antenna
(e.g., a small dipole). This allows for potentially higher coupling
between the pair. Furthermore, "electric" antennas (e.g., dipoles
and monopoles) or a combination of magnetic and electric antennas
may be used.
[0050] FIG. 3 is another functional block diagram showing core and
ancillary components of the wireless power transfer system 300 of
FIG. 1. The wireless power transfer system 300 illustrates a
communication link 376, a guidance link 366, and an alignment
mechanism 356 capable of mechanically moving one or both of the
base system induction coil 304 and the electric vehicle induction
coil 316 via base alignment system 352 and electric vehicle
alignment systems 354. The guidance link 366 may be capable of
bi-directional signaling, meaning that guidance signals may be
emitted by the base guidance system 362 or the electric vehicle
guidance system 364 or by both. As described above with reference
to FIG. 2, and assuming energy flow towards the electric vehicle
112, in FIG. 3 a base charging system power interface 348 may be
configured to provide power to a charging system power converter
336 from a power source, such as an AC or DC power supply 208. The
base charging system power converter 336 may receive AC or DC power
from the base charging system power interface 348 to excite the
base system induction coil 304 at or near its resonant frequency.
In some aspects, a base cooling system 335 may be coupled to the
base system induction coil 304. In some embodiments, when the base
system induction coil 304 is in operation, it may generate heat in
the base system induction coil 304 or in other nearby objects and
systems. The base cooling system 335 may be configured to cool the
base system induction coil 304 in order to prevent overheating
and/or damage of the base system induction coil 304.
[0051] The electric vehicle induction coil 316, when in the near
field coupling-mode region, may receive energy from the near field
coupling mode region to oscillate at or near the resonant
frequency. In some aspects, an electric vehicle (EV) cooling system
337 may be coupled to the electric vehicle induction coil 316. In
some embodiments, when the electric vehicle induction coil 316 is
in operation and receiving power from the base system induction
coil 304, it may generate heat in the electric vehicle induction
coil 316 or in other nearby objects and systems of the electric
vehicle. The EV cooling system 337 may be configured to cool the
electric vehicle induction coil 316 in order to prevent overheating
and/or damage of the electric vehicle induction coil 316. The
electric vehicle power converter 338 converts the oscillating
signal from the electric vehicle induction coil 316 to a power
signal suitable for charging a battery via the electric vehicle
power interface.
[0052] The base wireless charging system 302 includes a base
charging system controller 342 and the electric vehicle charging
system 314 includes an electric vehicle controller 344. The base
charging system controller 342 may include a base charging system
communication interface 358 to other systems (not shown) such as,
for example, a computer, and a power distribution center, or a
smart power grid. The electric vehicle controller 344 may include
an electric vehicle communication interface to other systems (not
shown) such as, for example, an on-board computer on the vehicle,
other battery charging controller, other electronic systems within
the vehicles, and remote electronic systems.
[0053] The base charging system controller 342 and electric vehicle
controller 344 may include subsystems or modules for specific
application with separate communication channels. These
communications channels may be separate physical channels or
separate logical channels. As non-limiting examples, a base
charging alignment system 352 may communicate with an electric
vehicle alignment system 354 through a communication link 376 to
provide a feedback mechanism for more closely aligning the base
coupler 304 and electric vehicle coupler 316, either via
autonomous, mechanical (kinematic) alignment or with operator
assistance. Similarly, a base charging guidance system 362 may
communicate with an electric vehicle guidance system 364 through a
guidance link 366 to provide a feedback mechanism to guide an
operator in aligning the base coupler 304 and electric vehicle
coupler 316. In addition, there may be separate general-purpose
communication links (e.g., channels) supported by base charging
communication system 372 and electric vehicle communication system
374 for communicating other information between the base wireless
charging system 302 and the electric vehicle charging system 314.
This information may include information about electric vehicle
characteristics, battery characteristics, charging status, and
power capabilities of both the base wireless charging system 302
and the electric vehicle charging system 314, as well as
maintenance and diagnostic data for the electric vehicle 112. These
communication channels may be separate physical communication
channels such as, for example, Bluetooth, ZigBee, cellular,
etc.
[0054] Electric vehicle controller 344 may also include a battery
management system (BMS) (not shown) that manages charge and
discharge of the electric vehicle principal battery, a parking
assistance system based on microwave or ultrasonic radar
principles, a brake system configured to perform a semi-automatic
parking operation, and a steering wheel servo system configured to
assist with a largely automated parking `park by wire` that may
provide higher parking accuracy, thus reducing the need for
mechanical horizontal induction coil alignment in any of the base
wireless charging system 102a and the electric vehicle charging
system 114. Further, electric vehicle controller 344 may be
configured to communicate with electronics of the electric vehicle
112. For example, electric vehicle controller 344 may be configured
to communicate with visual output devices (e.g., a dashboard
display), acoustic/audio output devices (e.g., buzzer, speakers),
mechanical input devices (e.g., keyboard, touch screen, and
pointing devices such as joystick, trackball, etc.), and audio
input devices (e.g., microphone with electronic voice
recognition).
[0055] Furthermore, the wireless power transfer system 300 may
include detection and sensor systems. For example, the wireless
power transfer system 300 may include sensors for use with systems
to properly guide the driver or the vehicle to the charging spot,
sensors to mutually align the induction coils with the required
separation/coupling, sensors to detect objects that may obstruct
the electric vehicle induction coil 316 from moving to a particular
height and/or position to achieve coupling, and safety sensors for
use with systems to perform a reliable, damage free, and safe
operation of the system. For example, a safety sensor may include a
sensor for detection of presence of animals or children approaching
the wireless power induction coils 104a, 116 beyond a safety
radius, detection of metal objects near the base system induction
coil 304 that may be heated up (induction heating), detection of
hazardous events such as incandescent objects on the base system
induction coil 304, and temperature monitoring of the base wireless
charging system 302 and electric vehicle charging system 214
components.
[0056] The wireless power transfer system 300 may also support
plug-in charging via a wired connection. A wired charge port may
integrate the outputs of the two different chargers prior to
transferring power to or from the electric vehicle 112. Switching
circuits may provide the functionality as needed to support both
wireless charging and charging via a wired charge port.
[0057] To communicate between a base wireless charging system 302
and an electric vehicle charging system 314, the wireless power
transfer system 300 may use both in-band signaling and an RF data
modem (e.g., Ethernet over radio in an unlicensed band). The
out-of-band communication may provide sufficient bandwidth for the
allocation of value-add services to the vehicle user/owner. A low
depth amplitude or phase modulation of the wireless power carrier
may serve as an in-band signaling system with minimal
interference.
[0058] In addition, some communication may be performed via the
wireless power link without using specific communications antennas.
For example, the wireless power induction coils 304 and 316 may
also be configured to act as wireless communication transmitters.
Thus, some implementations of the base wireless charging system 302
may include a controller (not shown) for enabling keying type
protocol on the wireless power path. By keying the transmit power
level (amplitude shift keying) at predefined intervals with a
predefined protocol, the receiver may detect a serial communication
from the transmitter. The base charging system power converter 336
may include a load sensing circuit (not shown) for detecting the
presence or absence of active electric vehicle receivers in the
vicinity of the near field generated by the base system induction
coil 304. By way of example, a load sensing circuit monitors the
current flowing to the power amplifier, which is affected by the
presence or absence of active receivers in the vicinity of the near
field generated by base system induction coil 104a. Detection of
changes to the loading on the power amplifier may be monitored by
the base charging system controller 342 for use in determining
whether to enable the oscillator for transmitting energy, to
communicate with an active receiver, or a combination thereof.
[0059] FIG. 4A is a diagram of an electric vehicle charging system
400 illustrating a configuration of a heat sink 410 coupled to a
vehicle pad 420 in accordance with an embodiment. As shown, the
vehicle pad 420 comprises a ferrite portion 421 and a coil portion
422. The vehicle pad 420 may also be referred to herein as the
power receiving unit (PRU) 420. The PRU 420 may be similar to the
electric vehicle charging system 114, 214, 314 (FIGS. 1-3) and the
electric vehicle induction coil 116, 216, and 316 (FIGS. 1-3) and
be configured to receive a wireless field from the base system
induction coil 104, 204, 304 of the base wireless charging system
102, 202, and 302 (FIGS. 1-3). In some embodiments the coil/antenna
portion 422 of the PRU 420 may span a majority of the dimension of
the PTU 420. In some aspects, the coil portion 422 may comprise a
copper coil. The heat sink 410, as shown in FIG. 4A is located in a
position internal to or above the ferrite portion 421 and the coil
portion 422 of the PRU 420. In some aspects, the heat sink 410 may
comprise a metallic heat sink or water cooled heat exchanger. In
some embodiments, the location of the metallic heat sink 410 as
shown in FIG. 4A may add eddy current losses to the wireless power
transfer systems 100-300 of FIGS. 1-3 due to high magnetic field
exposure over the coil portion 422.
[0060] FIG. 4B is a diagram of an electric vehicle charging system
450 illustrating a configuration of a heat sink 460 coupled to the
vehicle pad 420 in accordance with an embodiment. The electric
vehicle charging system 450 is similar to and adapted from the
electric vehicle charging system 400 of FIG. 4A. Only differences
between the electric vehicle charging systems 400 and 450 are
discussed for the sake of brevity.
[0061] As shown in FIG. 4B, the heat sink 460 is located in a
position internal to or above only the ferrite portion 421. The
ferrite portion 421 channels or concentrates the magnetic flux
received from the base system induction coil 304 such that an area
above a second side of the ferrite material 421 facing toward the
interior of the electric vehicle has a reduced or minimal magnetic
field. Accordingly, any metallic portions of the heat sink 460
would not be significantly influenced by the small magnetic field
above the second side of the ferrite material 421 and would not
generate, or would generate only minimal eddy currents. The reduced
eddy currents in the metallic portions of the heat sink 460 would
therefore generate fewer losses than the metallic portions of the
heat sink 410 of FIG. 4A and may result in a better efficiency of
the electric vehicle charging system 450 than the electric vehicle
charging system 400.
[0062] In some aspects, it may be desirable to have portions of a
heat sink located above the coil portion 422 in order to better
remove the heat generated by the coil portion 422 during wireless
power transfer. FIG. 5A is a diagram of an electric vehicle
charging system 500 illustrating a configuration of a heat sink 510
coupled to the vehicle pad 420 in accordance with an embodiment.
The electric vehicle charging system 500 is similar to and adapted
from the electric vehicle charging system 450 of FIG. 4B. Only
differences between the electric vehicle charging systems 450 and
500 are discussed for the sake of brevity.
[0063] As shown in FIG. 5A, the heat sink 510 is located in a
position internal to or above the ferrite portion 421. The heat
sink 510 comprises metallic fins or extensions that extend over the
coil portion 422. In some embodiments, the metallic extensions may
comprise metallic pipes for carrying cooling liquids such as water.
In some aspects, the number, size, and/or length of the extensions
may be based on their ability and effectiveness at convective or
conductive heat transfer in relation to any impact on the magnetic
field. In some embodiments, the length of the extensions of the
heat sink 510 may be such that the extensions do not affect the
magnetic field generated by the base system induction coil 304. The
extensions may further be arranged having a horizontal separation
between individual extensions of a value such that at least one of
convective/conductive heat removal, the aesthetics, and surface
grip are maximized. As shown, the extensions of the heat sink 510
are configured such that they are positioned substantially parallel
to the magnetic field lines of the magnetic field generated by the
base system induction coil 304. As discussed above, the portions of
the heat sink 510 located above the coil portion 422 may help to
pull losses out from the coil portion 422 toward the center of the
heat sink 510. In some aspects, the parallel configuration of the
metallic extensions of the heat sink 510 helps minimize any eddy
currents that would be generated in the metallic extensions. The
reduced eddy currents in the metallic extensions of the heat sink
510 may therefore generate fewer losses than the metallic portions
of the heat sink 410 of FIG. 4A located over coil portion 422 while
still removing heat/losses from the coil portion 422. Accordingly,
the use of the heat sink 510 may result in a better efficiency of
the electric vehicle charging system 500 than the electric vehicle
charging system 400.
[0064] FIG. 5B is a diagram of an electric vehicle charging system
550 illustrating a configuration of a first heat sink 560 coupled
to the vehicle pad 420 and a second heat sink 561 in accordance
with an embodiment. The electric vehicle charging system 550 is
similar to and adapted from the electric vehicle charging system
500 of FIG. 5A. Only differences between the electric vehicle
charging systems 500 and 550 are discussed for the sake of
brevity.
[0065] As shown in FIG. 5B, the heat sink 560 is located in a
position internal to or above the ferrite portion 421. The heat
sink 560 comprises metallic fins or extensions that extend over the
coil portion 422. In some aspects, the heat sink 561 may comprise a
metallic cavity or tank for housing a cooling liquid. In some
embodiments, the metallic extensions may comprise metallic pipes
for carrying cooling liquids such as water. In some aspects, the
number, size, and/or length of the extensions may be based on their
ability and effectiveness at convective/conductive heat transfer in
relation to any impact on the magnetic field. As shown, the
extensions of the heat sink 560 are configured such that they are
positioned substantially parallel to the magnetic field lines of
the magnetic field generated by the base system induction coil 304.
As discussed above, the portions of the heat sink 560 located above
the coil portion 422 may help to pull losses out from the coil
portion 422 toward the second heat sink 561. The heat sink 561 may
be located in position outside an area defined by the vehicle pad
420. In some aspects, the location outside the area defined by the
vehicle pad 420 may be exposed to a reduced or minimal magnetic
field that is generated from the base system induction coil 304.
Accordingly, the metallic portions of the heat sink 561 may have
reduced eddy currents generated as a result of the magnetic field.
In some aspects, the parallel configuration of the metallic
extensions/pipes of the heat sink 560 helps minimize any eddy
currents that would be generated in the metallic extensions. The
reduced eddy currents in the metallic extensions of the heat sink
510 may therefore generate fewer losses than the metallic portions
of the heat sink 410 of FIG. 4A located over coil portion 422 while
still removing heat/losses from the coil portion 422. Additionally,
the use of the second heat sink 561 may be located above power
electronics (e.g., switch circuits, processors, memory circuits,
etc.) to help remove heat generated by those power electronics.
Accordingly, the use of the heat sink 510 may result in a better
efficiency of the electric vehicle charging system 500 than the
electric vehicle charging system 400.
[0066] In some aspects, it may be desirable to utilize non-metallic
water cooling applications to minimize or eliminate eddy current
losses that are generated by using metallic heat sinks or metallic
liquid cooled heat exchangers. FIG. 6A is an inverted diagram of an
electric vehicle charging system 600 illustrating a configuration
of a heat sink 610 coupled to the vehicle pad 420 in accordance
with an embodiment. For FIGS. 6A-7B, the top portion of the figures
would be facing a base pad while the bottom portion would face the
interior of the electric vehicle. The electric vehicle charging
system 600 further comprises a potting compound 611 and a housing
615. In some aspects, the potting compound 611 may be configured to
maintain the vehicle pad 420 and the heat sink 610 within the
housing 615. In some embodiments, the heat sink 610 comprises a
non-metallic pipe or tube used for controlling the flow of a
cooling liquid running through the pipe/tube. In some aspects, the
heat sink 610 may comprise a plastic, glass, fiber-glass, ceramic
or other non-metallic material.
[0067] As shown in FIG. 6A, the heat sink 610 is located in a
position internal to or above the ferrite portion 421. The heat
sink 610 comprises a non-metallic tube that can extend over the
entire vehicle pad 420 (e.g., the ferrite portion 421 and the coil
portion 422) in order to extract the heat/losses generated in the
vehicle pad 420. Since the heat sink 610 does not contain any
metallic material, it may not produce eddy currents that could
increase losses and/or reduce the efficiency of the electric
vehicle charging system 600. Accordingly, the use of the heat sink
610 may result in a better efficiency of the electric vehicle
charging system 600 than the electric vehicle charging system 400
of FIG. 4A.
[0068] FIG. 6B is an inverted diagram of an electric vehicle
charging system 650 illustrating a configuration of an electronic
circuit 660 coupled to the heat sink 610 in accordance with an
embodiment. The electric vehicle charging system 650 is similar to
and adapted from the electric vehicle charging system 600 of FIG.
6A. Only differences between the electric vehicle charging systems
600 and 650 are discussed for the sake of brevity.
[0069] As shown in FIG. 6B, the electronic circuit 660 is located
in a position internal to or above the heat sink 610. In such a
configuration, the heat sink 610 may be configured to extract or
reduce the heat/losses of both the vehicle pad 420 and the
electronic circuit 660. In some aspects, the electronic circuit 660
comprises electrical components used for controlling, monitoring,
and/or facilitating wireless power transfer.
[0070] FIG. 7A is an inverted diagram of an electric vehicle
charging system 700 illustrating a configuration of a non-metallic
heat exchanger 711 surrounding the non-metallic heat sink 710 in
accordance with an embodiment. The electric vehicle charging system
700 is similar to and adapted from the electric vehicle charging
system 600 of FIG. 6A. Only differences between the electric
vehicle charging systems 600 and 700 are discussed for the sake of
brevity.
[0071] As shown in FIG. 7A, the non-metallic heat exchanger 711 is
located in a position internal to or above the vehicle pad 420. In
some aspects, the non-metallic heat exchanger 711 surrounds the
non-metallic heat sink 710. In some embodiments, the non-metallic
heat exchanger 711 contains a cooling liquid inside the
non-metallic heat exchanger 711. The non-metallic heat sink 710 may
comprise a non-metallic tube/pipe for controlling the flow of a
cooling liquid and the tube/pipe can extend over the entire vehicle
pad 420 in order to extract the heat/losses generated in the
vehicle pad 420. Since the heat sink 710 and the heat exchanger 711
do not contain any metallic material, they may not produce eddy
currents that could increase losses and/or reduce the efficiency of
the electric vehicle charging system 700. Accordingly, the use of
the heat sink 710 and the heat exchanger 711 may result in a better
efficiency of the electric vehicle charging system 700 than the
electric vehicle charging system 400 of FIG. 4A.
[0072] FIG. 7B is an inverted diagram of an electric vehicle
charging system 750 illustrating a configuration of an electronic
circuit 760 coupled to the heat exchanger 711 in accordance with an
embodiment. The electric vehicle charging system 750 is similar to
and adapted from the electric vehicle charging system 700 of FIG.
7A. Only differences between the electric vehicle charging systems
700 and 750 are discussed for the sake of brevity.
[0073] As shown in FIG. 7B, the electronic circuit 760 is located
in a position internal to or above the heat exchanger 711. In such
a configuration, the heat exchanger 711 and heat sink 710 may be
configured to extract or reduce the heat/losses of both the vehicle
pad 420 and the electronic circuit 760. In some aspects, the
electronic circuit 760 comprises electrical components used for
controlling, monitoring, and/or facilitating wireless power
transfer.
[0074] FIG. 8 is a diagram of an electric vehicle charging system
800 illustrating a configuration of a liquid heat sink 810
surrounding the vehicle pad 420 in accordance with an embodiment.
The electric vehicle charging system 800 is similar to and adapted
from the electric vehicle charging system 700 of FIG. 7A. Only
differences between the electric vehicle charging systems 700 and
800 are discussed for the sake of brevity.
[0075] As shown in FIG. 8, the liquid heat sink 810 is located
within the housing 615 and is allowed to flow directly around the
vehicle pad 420. In some aspects, the liquid heat sink 810
comprises water or another cooling liquid. In some aspects, the
liquid heat sink may be configured flow around the vehicle to
extract or reduce the heat/losses of both the vehicle pad 420
and/or an electronic circuit (not shown) similar to the electronic
circuit 660 and 760 of FIGS. 6B and 7B. Since the heat sink 810
does not contain any metallic material, it may not produce eddy
currents that could increase losses and/or reduce the efficiency of
the electric vehicle charging system 800. Accordingly, the use of
the liquid heat sink 810 may result in a better efficiency of the
electric vehicle charging system 800 than the electric vehicle
charging system 400 of FIG. 4A.
[0076] The metallic and non-metallic heat sinks and/or heat
exchangers 460, 510, 560, 610, 710, 711, and 810 of FIGS. 4B-8 may
also be applicable to wireless power transmitters (e.g., base
wireless charging system 102, 202, 302 of FIGS. 1-3). In addition,
any combinations of any of the above metallic and non-metallic heat
sinks and/or heat exchangers described above may also be
possible.
[0077] FIG. 9 is a flowchart depicting a method for managing
thermal power loss according to the disclosure. The method shown in
FIG. 9 may be implemented via one or more devices in the wireless
power transfer systems 100-800 similar to the electric vehicle
wireless charging system 114, 214, 314, the vehicle pad 420, the
heat sinks and/or heat exchangers 460, 510, 560, 610, 710, 711, and
810 of FIGS. 1-8. Although the method 900 is described herein with
reference to a particular order, in various implementations, blocks
herein may be performed in a different order, or omitted, and
additional blocks may be added.
[0078] At block 902, the electric vehicle wireless charging system
(e.g., electric vehicle wireless charging system 314) receives, via
a receiver circuit, wireless power via a magnetic field sufficient
to power or charge a wireless power receiver. The receiver circuit
comprises a receiver coil and a ferrite material having a first
side coupled to the receiver coil. At block 904, the electric
vehicle wireless charging system cools the receiver circuit using a
first heat exchanger coupled to a second side of the ferrite
material.
[0079] Another aspect of the invention includes an electric vehicle
wireless charging system 314. The electric vehicle wireless
charging system comprises means for receiving wireless power from a
wireless power transmitter via a magnetic field sufficient to
charge or power a load of the apparatus. In some embodiments, the
means for receiving may comprise an electric vehicle induction coil
316 or some similar device configured to receive wireless power.
The electric vehicle wireless charging system 314 further comprises
a ferrite material having a first side coupled to the means for
receiving. The ferrite material may comprise iron oxide with
nickel, zinc, and/or manganese material or another ferrite
material. The electric vehicle wireless charging system 314 also
includes means for cooling the receiving means using a first heat
exchanger coupled to a second side of the ferrite material. The
cooling means may comprise a heat sink/heat exchanger 460, 510,
560, 610, 710, 711, and/or 810 or a similar component or device
configured to cool the means for receiving.
[0080] The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0081] Information and signals may be represented using any of a
variety of different technologies and techniques. For example,
data, instructions, commands, information, signals, bits, symbols,
and chips that may be referenced throughout the above description
may be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles, or any
combination thereof.
[0082] The various illustrative logical blocks, modules, circuits,
and algorithm steps described in connection with the embodiments
disclosed herein may be implemented as electronic hardware,
computer software, or combinations of both. To clearly illustrate
this interchangeability of hardware and software, various
illustrative components, blocks, modules, circuits, and steps have
been described above generally in terms of their functionality.
Whether such functionality is implemented as hardware or software
depends upon the particular application and design constraints
imposed on the overall system. The described functionality may be
implemented in varying ways for each particular application, but
such implementation decisions should not be interpreted as causing
a departure from the scope of the embodiments of the invention.
[0083] The various illustrative blocks, modules, and circuits
described in connection with the embodiments disclosed herein may
be implemented or performed with a general purpose processor, a
Digital Signal Processor (DSP), an Application Specific Integrated
Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general purpose
processor may be a microprocessor, but in the alternative, the
processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0084] The steps of a method or algorithm and functions described
in connection with the embodiments disclosed herein may be embodied
directly in hardware, in a software module executed by a processor,
or in a combination of the two. If implemented in software, the
functions may be stored on or transmitted over as one or more
instructions or code on a tangible, non-transitory
computer-readable medium. A software module may reside in Random
Access Memory (RAM), flash memory, Read Only Memory (ROM),
Electrically Programmable ROM (EPROM), Electrically Erasable
Programmable ROM (EEPROM), registers, hard disk, a removable disk,
a CD ROM, or any other form of storage medium known in the art. A
storage medium is coupled to the processor such that the processor
can read information from, and write information to, the storage
medium. In the alternative, the storage medium may be integral to
the processor. Disk and disc, as used herein, includes compact disc
(CD), laser disc, optical disc, digital versatile disc (DVD),
floppy disk and Blu-ray disc where disks usually reproduce data
magnetically, while discs reproduce data optically with lasers.
Combinations of the above should also be included within the scope
of computer readable media. The processor and the storage medium
may reside in an ASIC. For purposes of summarizing the disclosure,
certain aspects, advantages and novel features of the inventions
have been described herein. It is to be understood that not
necessarily all such advantages may be achieved in accordance with
any particular embodiment of the invention. Thus, the invention may
be embodied or carried out in a manner that achieves or optimizes
one advantage or group of advantages as taught herein without
necessarily achieving other advantages as may be taught or
suggested herein.
[0085] Various modifications of the above described embodiments
will be readily apparent, and the generic principles defined herein
may be applied to other embodiments without departing from the
spirit or scope of the invention. Thus, the present invention is
not intended to be limited to the embodiments shown herein but is
to be accorded the widest scope consistent with the principles and
novel features disclosed herein.
* * * * *